When I receive email from one specific coworker, I see the mail as received from “name@MISSING_DOMAIN” while when I look into the header, which looks fine by the way, is not in there.
Maybe a small hint, his name is “Someone Someone [Company]”. The square brackets, I mean.
Strictly, it might be possible that these characters are not allowed in a recipient’s name, but any other client allows it. On other clients, the name shows correctly and the domain name is parsed correctly.
Can you fix this issue?
Dirk.